Buggy code:
public abstract class DotnetCompile extends DotnetBaseMatchingTask { private String references ; private boolean includeDefaultReferences = true ; private File win32icon ; private File win32res ; private boolean failOnError ; private Path referenceFiles ; private boolean optimize ; protected Vector definitionList = new Vector ( ) ; protected Vector resources = new Vector ( ) ; protected String executable ; protected static final String REFERENCE_OPTION = "//reference:" ; protected boolean debug ; private int warnLevel ; protected String mainClass ; protected String extraOptions ; protected String targetType ; protected boolean utf8output = false ; protected String additionalModules ; protected Vector referenceFilesets = new Vector ( ) ; private boolean useResponseFile = false ; private static final int AUTOMATIC_RESPONSE_FILE_THRESHOLD = 64 ; public DotnetCompile ( ) { } public void clear ( ) { } public void setReferences ( String s ) { } protected String getReferencesParameter ( ) { if ( notEmpty ( references ) ) { if ( isWindows ) { return ( ( ( DotnetCompile . REFERENCE_OPTION ) + '\"' ) + ( references ) ) + '\"' ; } else { <START_BUG> return references ; <END_BUG> } } else { return null ; } } public void setReferenceFiles ( Path path ) { } public void addReference ( FileSet reference ) { } protected String getReferenceFilesParameter ( ) { } public void setIncludeDefaultReferences ( boolean f ) { } public boolean getIncludeDefaultReferences ( ) { } protected String getIncludeDefaultReferencesParameter ( ) { } public void setOptimize ( boolean f ) { } public boolean getOptimize ( ) { } protected String getOptimizeParameter ( ) { } public void setDebug ( boolean f ) { } public boolean getDebug ( ) { } protected String getDebugParameter ( ) { } public void setWarnLevel ( int warnLevel ) { } public int getWarnLevel ( ) { } protected String getWarnLevelParameter ( ) { } public void setMainClass ( String mainClass ) { } public String getMainClass ( ) { } protected String getMainClassParameter ( ) { } public void setExtraOptions ( String extraOptions ) { } public String getExtraOptions ( ) { } protected String getExtraOptionsParameter ( ) { } protected String [ ] getExtraOptionsParameters ( ) { } public void setDestDir ( File dirName ) { } public void setTargetType ( DotnetCompile . TargetTypes targetType ) { } public void setTargetType ( String ttype ) throws BuildException { } public String getTargetType ( ) { } protected String getTargetTypeParameter ( ) { } public void setWin32Icon ( File fileName ) { } protected String getWin32IconParameter ( ) { } public void setWin32Res ( File fileName ) { } public File getWin32Res ( ) { } protected String getWin32ResParameter ( ) { } public void setUtf8Output ( boolean enabled ) { } protected String getUtf8OutputParameter ( ) { } public void addDefine ( DotnetDefine define ) { } protected String getDefinitionsParameter ( ) throws BuildException { } public void setAdditionalModules ( String params ) { } protected String getAdditionalModulesParameter ( ) { } protected String getDestFileParameter ( ) { } public void setFailOnError ( boolean b ) { } public boolean getFailOnError ( ) { } public void addResource ( DotnetResource resource ) { } protected String getExecutable ( ) { } public void setExecutable ( String executable ) { } protected boolean notEmpty ( String s ) { } protected void validate ( ) throws BuildException { } public String getFilePattern ( ) { } public boolean isUseResponseFile ( ) { } public void setUseResponseFile ( boolean useResponseFile ) { } public void execute ( ) throws BuildException { } public abstract String getReferenceDelimiter ( ) { } public abstract String getFileExtension ( ) { } protected void fillInSharedParameters ( NetCommand command ) { } protected void addResources ( NetCommand command ) { } protected abstract String createResourceParameter ( DotnetResource resource ) { } protected int addReferenceFilesets ( NetCommand command , long outputTimestamp ) { } protected NetCommand createNetCommand ( ) { } protected abstract void addCompilerSpecificOptions ( NetCommand command ) { } public String getDefinitionsDelimiter ( ) { } protected static boolean isFileManagedBinary ( File file ) { } public static class TargetTypes extends EnumeratedAttribute { public String [ ] getValues ( ) { } } }

Fix:
return ( DotnetCompile . REFERENCE_OPTION ) + ( references ) ;